A vehicle such as an automobile depends upon reliable and failsafe delivery of power to various vehicle components. For example, a failure to deliver power or communications to one or more vehicle parking restraint mechanisms, e.g., a parking brake, engagement of gears in a vehicle powertrain, etc., could put a vehicle driver, other vehicle occupants, and/or people outside the vehicle at risk. Reliable parking mechanisms are particularly important in the case of an autonomous vehicle, i.e., a vehicle in which some or all operations conventionally controlled by a human driver are controlled and carried out by components in the vehicle without driver intervention.